Women who experience intimate partner violence (IPV) have rates of substance misuse that are 2 to 7 times higher than women nationally. IPV-exposed women also have extremely high rates of risky sexual behavior (behavior that puts women at risk for HIV, sexually transmitted infections, and unwanted pregnancies). Despite such high rates, little research has examined mechanisms by which IPV may increase the risk of substance use and risky sexual behavior. IPV-exposed women are more likely to suffer from PTSD symptoms, which may make them especially vulnerable to these problems. Women's recurrent experience of IPV and chronic exposure to traumatic stressors (e.g., abusive partner) likely contribute to unique profiles of PTSD symptoms, which in turn, may be related to use of different classes of substances and risky sexual behavior. Yet no data exist to test the hypothesis that PTSD symptoms trigger substance use and risky sexual behavior among this high risk population. Aims: Among IPV-exposed women, the proposed study aims to: 1. Test within-person effects of acute PTSD symptom severity by cluster on proximal (a) drug, (b) alcohol, and (c) tobacco use. 2. Test within-person effects of acute PTSD symptom severity by cluster on proximal risky sexual behavior and to test the potentially mediating and moderating effects of (a) drug and (b) alcohol use on these relationships. 3. Test the moderating effects of race/ethnicity and culturally relevant risk and protective factors on the within-person associations between acute PTSD symptom severity by cluster and (a) drug, (b) alcohol, and (c) tobacco use, and separately on (d) risky sexual behavior. The short-term objective is to evaluate contingencies among PTSD symptom severity by cluster, substance use, and risky sexual behavior. Because integrated interventions for this special population have more effective outcomes, the long-term objective is to develop integrated intervention and prevention strategies addressing symptoms of PTSD, substance use, risky sexual behavior, and IPV-related problems to be implemented in community settings. Methods: An experience sampling method will be used to collect intensive longitudinal data in near real time from 300 IPV-exposed women in the community, allowing experiences and behaviors to be captured as they unfold in their natural environment. Women will use cell phones connected to interactive voice response technology to report their experiences 4 times a day for 30 days to determine if PTSD symptoms trigger substance use and risky sexual behavior at the within-person level. The sample will be stratified to examine potential moderating effects of race/ethnicity (100 each, African American, Latina, and White women). Significance: The proposed project addresses the critical need to determine mechanisms through which IPV is related to increased drug, alcohol, and tobacco use and risky sexual behavior so that integrated intervention and prevention strategies tailored to the unique needs of this population can be developed. Reducing substance use and risky sexual behavior among IPV-exposed women will improve the health of countless women in our nation.